Commitments And Contingencies (Narrative) (Details) (USD $)	0 Months Ended				1 Months Ended		3 Months Ended										0 Months Ended	3 Months Ended		0 Months Ended	3 Months Ended
	Aug. 06, 2011 additional_companies companies	Sep. 01, 2010 companies patents	Mar. 25, 2010	Oct. 23, 2009	Oct. 31, 2008 companies	Jan. 31, 2008 technology_companies	Apr. 01, 2012	Nov. 26, 2011 patents	Nov. 16, 2011 actions patents	May 23, 2011	Mar. 03, 2011 claims	Sep. 14, 2010 patents	Nov. 29, 2008 patents	Nov. 30, 2007 patents	Apr. 01, 2012 46 To 60 Days [Member]	Apr. 01, 2012 31 To 45 Days [Member]	Feb. 17, 2012 Minimum [Member]	Apr. 01, 2012 Minimum [Member] 46 To 60 Days [Member]	Apr. 01, 2012 Minimum [Member] 31 To 45 Days [Member]	Feb. 17, 2012 Maximum [Member]	Apr. 01, 2012 Maximum [Member] 46 To 60 Days [Member]	Apr. 01, 2012 Maximum [Member] 31 To 45 Days [Member]	Apr. 01, 2012 Chief Executive Officer [Member]	Apr. 01, 2012 Senior Vice President Of Worldwide Operations And Support [Member]	Apr. 01, 2012 Other Key Executives [Member]	Apr. 03, 2012 Litigation Filed [Member] patents
Commitments And Contingencies [Line Items]
Operating leases expiration date							2026
Percentage of cancelable orders															50.00%	25.00%
Required notice period prior to the expected shipment date (in days)																		46 days	31 days		60 days	45 days
Number of days for non-cancellation of purchase obligations prior to expected shipment date (in days)							30 days
Non-cancelable purchase commitments							$ 176,300,000
Number of weeks for which salary is payable upon termination of employment without cause (in weeks)																							P52W	P39W	P26W
Continued vesting period after termination without cause (in years)							1 year
Number of years after change of control to trigger full accelerated vest of unvested portion of stock options (in years)																							1 year
Maximum number of years covered by accelerated vest for other key executives if term without cause is within one year of change in control (in years)																									2 years
Number of other technology companies sued for patent infringement (in technology companies)						6
Amount of defendants' joint request for costs which have not been collected or recognized										$ 103,000
Recurring period that courts instructed parties to submit status reports by (in months)			6 months
Number of other companies lawsuit was filed against (in companies)	16	7			30
Number of patents company is accused of infringing (in patents)		2						6				8
Number of wired claims rejected in the patent (in claims)											5
Number of additional companies sued in a separate suit (in additional companies)	14
Number of patents in which company filed judgement action for nonInfringement and invalidity (in patents)									17					8
Number of actions brought against end user customers and other companies (in actions)									15
Number of patents attempted to be read on company ProSecure UTM series of products (in patents)								4
Number of patents that allegedly read on certain access points and wireless routers and gateways with multiple antennas (in patents)								2
Length of trial period (in days)																	5 days			10 days
Number of patents company filed suit for infringement of (in patents)																										4
Number of patents dropped from the case (in patents)													3
Number of patents at issue remaining in the case (in patents)													5
Period to withdraw motion to dismiss litigation (in days)				5 days